Integrated eccentric motor and pump

ABSTRACT

A pump is provided. The pump includes a fluid inlet section; a fluid outlet section; a stator axially between the fluid inlet section and the fluid outlet section; a rotor axially between the fluid inlet section and the fluid outlet section, the rotor and the stator defining a fluid flow space radially therebetween; a movable inlet guide configured for guiding fluid flow from the fluid inlet section into the fluid flow space; and a movable outlet guide configured for guiding fluid flow from the fluid flow space into the fluid outlet section. The rotor is rotatable inside of the stator by electromagnetic forces urging the rotor towards the stator. Rotation of the stator and movement of the inlet guide and the outlet guide create a pressure in a first portion of the fluid flow space that forces fluid from the fluid flow space through the fluid outlet section and create a vacuum in a second portion of the fluid flow space that pulls fluid from the fluid inlet section into the fluid flow space. A method of forming a pump is also provided.

The present disclosure relates generally to pump and more specifically to pumps of automotive vehicle transmissions.

BACKGROUND

U.S. Pat. No. 6,109,887 discloses a pump including an integrated motor and rotor. U.S. Pub. No. 2014/0119963 discloses an integrated electric oil pump including a gerotor pump. U.S. Pub. No. 2015/0288249 discloses an eccentric motor.

SUMMARY OF THE INVENTION

A pump is provided. The pump includes a fluid inlet section; a fluid outlet section; a stator axially between the fluid inlet section and the fluid outlet section; a rotor axially between the fluid inlet section and the fluid outlet section, the rotor and the stator defining a fluid flow space radially therebetween; a movable inlet guide configured for guiding fluid flow from the fluid inlet section into the fluid flow space; and a movable outlet guide configured for guiding fluid flow from the fluid flow space into the fluid outlet section. The rotor is rotatable inside of the stator by electromagnetic forces urging the rotor towards the stator. Rotation of the stator and movement of the inlet guide and the outlet guide create a pressure in a first portion of the fluid flow space that forces fluid from the fluid flow space through the fluid outlet section and create a vacuum in a second portion of the fluid flow space that pulls fluid from the fluid inlet section into the fluid flow space.

A method of forming a pump is also provided. The method includes providing a rotor radially inside of a stator; rotatably fixing a movable inlet guide to a first axial side of the rotor; rotatably fixing a movable outlet guide to second axial side of the rotor; providing a fluid inlet section upstream of the movable inlet guide; and providing a fluid outlet section downstream of the movable outlet guide, the rotor and the stator defining a fluid flow space radially therebetween, the movable inlet guide configured for guiding fluid flow from the fluid inlet section into the fluid flow space, the movable outlet guide configured for guiding fluid flow from the fluid flow space into the fluid outlet section, the rotor being rotatable inside of the stator by electromagnetic forces urging the rotor towards the stator, rotation of the stator and movement of the inlet guide and the outlet guide creating a pressure in a first portion of the fluid flow space that forces fluid from the fluid flow space through the fluid outlet section and creating a vacuum in a second portion of the fluid flow space that pulls fluid from the fluid inlet section into the fluid flow space.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described below by reference to the following drawings, in which:

FIG. 1 schematically shows a cross-sectional side view of a pump for an automotive vehicle transmission according to an embodiment of the present invention; and

FIG. 2 shows an exploded cross-sectional perspective view of the pump shown in FIG. 1; and

FIG. 3 shows a plan view of the stator, rotor and a swash plate of the pump shown in FIGS. 1 and 2.

DETAILED DESCRIPTION

The disclosure provides a space-saving electrically driven auxiliary pump including a rotor and stator of a motor that are dual purposed as the rotor and stator of the pump. The rotor is positioned inside the stator using a gerotor pump, for example, or internal gear pump, vane pump, or several other pump types. An electric current is sent through at least four stator windings to create a magnetic field pulling the rotor towards that coil in order to complete a magnetic circuit formed by the legs of the stator. Movement of the rotor towards the coil displaces fluid thus creating pressure, and a vacuum is created on the other side of the rotor. As the rotor travels toward the first coil, the next coil is energized to roll the rotor around the inside of the stator pumping fluid from inlet to outlet. Swash plates serve to align the high pressure side with the outlet and the low pressure side with the inlet.

FIG. 1 schematically shows a cross-sectional side view of a pump 10 for an automotive vehicle transmission according to an embodiment of the present invention and FIG. 2 shows an exploded cross-sectional perspective view of pump 10. Pump 10 may be used in other contexts besides an automotive vehicle transmission. Pump 10 includes a fluid inlet section 12 of the housing, a fluid outlet section 14 of the housing, a stator 16 axially between fluid inlet section 12 and fluid outlet section 14 and a rotor 18 axially between fluid inlet section 12 and the fluid outlet section 14. Rotor 18 and stator 16 define a fluid flow space 20 radially therebetween. Pump 10 also includes a movable inlet guide 22 configured for guiding fluid flow from fluid inlet section 12 into fluid flow space 20 and a movable outlet guide 24 configured for guiding fluid flow from fluid flow space 20 into fluid outlet section 14.

Stator 16 is provided with a plurality of electrical windings 26 for generating electromagnetic forces in stator 16 to urge rotor 18 toward stator 16 such that rotor 18 rotates inside of stator 16. In this embodiment, stator 16 is provided with six electrical windings 26, but in other embodiments, stator 16 may be provided with any other amounts of windings 26 greater than three. Windings 26 are each wrapped around one of legs 28 of stator 16. Stator 16 includes a cylindrical ring 30 defining an outer circumference of stator 16, with each leg 28 protruding radially inward from cylindrical ring 30. Legs 28 each include a base 32 extending radially inward from an inner circumference of cylindrical ring 30, two branches 34 extending circumferentially from a radially inner end of base 32 in opposite circumferential directions, and a rounded radially innermost tip 36 protruding radially inward from branches 34. Windings 26 are wrapped around base 32 and held radially in place by the inner circumferential surface of cylindrical ring 30 and the outer circumferential surfaces of branches 34 and insulation layers may be provided over windings 26 to insulate windings from fluid flow space 20.

Rotor 18 in this embodiment is substantially star shaped and includes a plurality of radially outwardly extending protrusions 38. In this embodiment, rotor 18 includes five protrusions 38, but in other embodiments rotor 18 may include other amounts of protrusions 38, with the amount of protrusions 38 being one less than the number of windings 26. Protrusions 38 each include a radially outermost rounded tip 40. Rotor 18 is configured such that during rotation thereof, protrusions 38 sequentially enter into slots 42 between protrusions 38 to continuously vary the configuration of fluid flow space 20. When an electric current is sent through any one of windings 26 a magnetic field is created which pulls rotor 18 toward that winding 26 in order to complete a magnetic circuit formed by the legs 28 of the stator. As rotor 18 moves toward the winding 26, rotor 18 displaces fluid, with which fluid flow space 20 between the rotor and stator is filled, creating pressure. The movement of rotor 18 within stator 16 separates fluid flow space 20 into a first portion 20 a that is pressurized to force fluid out of outlet section 14 and a second portion 20 b that forms a vacuum to draw fluid into fluid flow space 20 from inlet section 12. As rotor 18 rotates within stator 16, the locations of first portion 20 a and second portion 20 b rotate about a center axis 44, with first portion 20 a being oriented on the opposite radial side of rotor 18 as second portion 20 b during the rotation.

In order to properly align inlet section 12 with second portion 20 b while isolating inlet section 12 from first portion 20 a, pump 10 includes movable inlet guide in the form of an inlet swash plate 22 upstream from rotor 18. In order to properly align outlet section 14 with first portion 20 a while isolating inlet section 12 from second section 20 b, pump 10 includes a movable outlet guide in the form of an outlet swash plate 24 downstream from rotor 18. Inlet swash plate 22 is configured to move to align the first portion 20 a of fluid flow space 20 with fluid inlet section 12 and outlet swash plate 24 is configured to move to align second portion 20 b of fluid flow space 20 with the fluid outlet section 14. More specifically, swash plates 22, 24 nonrotatably fixed to rotor 18 such that swash plates 22, 24 are configured to rotate about center axis 44 in the opposite direction as rotor 18. Swash plates 22, 24 are circumferentially offset from each other and on diametrically opposite radial sides of center axis 44 when viewed cross-sectionally in the axial direction. FIG. 3 illustrates an axially facing cross-sectional view stator 16, rotor 18, inlet swash plate 22 and outlet swash plate 24 from the fluid inlet side of pump 10. As shown in FIG. 3, swash plates 22, 24 are arranged in a complementary manner to form a circle, with each swash plate 22, 24 having a semi-circular cross section as define by the outer circumference of each swash plate 22, 24. Rotor 18 rotates about axis 44 in a rotational direction D1 while swash plates 22, 24 rotate about axis 44 in rotational direction D2.

Fluid from the high pressure side, i.e., portion 20 b, is pushed past outlet swash plate 24 and out the outlet section 14. At the same time, fluid is drawn in through inlet section 12 past inlet swash plate 22, filling the vacuum side, i.e., portion 20 a of rotor 18. When rotor 18 is travelling toward a first winding 26, the next winding 26 is energized and the process continues, rolling rotor 18 around the inside of stator 16 and pumping fluid from inlet section 12 to outlet section 14. Because the high and low pressure sides are continuously moving around stator 16, the swash plates are used to align the high pressure side with the outlet and the low pressure side with the inlet. Swash plates 22, 24 are centered on lips 12 a, 12 b of inlet section 12 and lips 14 a, 14 b of outlet section 14, respectively, and are driven by a pin 50 in rotor 18. This causes swash plates 22, 24 to rotate in the opposite direction that rotor 18 is rolling, maintaining alignment with the correct pressures.

Swash plate 22, 24 are fixed together and to rotor 18 by a pin 50 extending axially through rotor 18 and defining center axis 44. Rotor 18 is mounted eccentrically on pin 50 such that rotor 18 rotates eccentrically about center axis 44 during operation of pump 10. Inlet swash plate 22 is mounted on a first axial end of pin 50 and swash plate 24 is mounted on a second axial end of pin 50. Inlet section 12 includes an annular groove 52 for guiding the rotation of swash plate 22 and outlet section 14 similarly includes an annular groove 54 for guiding the rotation of swash plate 24. The rotation of rotor 18 causes swash plates 22, 24 to slide in respective annular grooves 52, 54 such that the outer circumference of each swash plate 22, 24 moves circumferentially, but does not move radially, while pin 50 and center axis 44 follow a circular path due to the eccentric placement of pin 50 on swash plates 22, 24.

Swash plates 22, 24 each include a connecting portion 22 a, 24 a and a guide portion 22 b, 24 b eccentrically fixed to the respective connecting portion 22 a, 24 a. Guide portions 22 b, 24 b each include a respective outer circumferential surface 22 c, 24 c, a respective longer radially extending surface 22 d, 24 d extending radially from the respective connecting portion 22 a, 24 a to a first edge of the respective outer circumferential surface 22 c, 24 c and a short radially extending surface 22 e, 24 e extending radially from the respective connecting portion 22 a, 24 a to a second edge of the respective outer circumferential surface 22 c, 24 c.

Each guide portion 22 b, 24 b also includes an axially protruding arc-shaped lip 22 f, 24 f configured for sliding in the annular groove respective annular groove 52, 54. Outer circumferential surfaces 22 c, 24 c of lips 22 f, 24 f slide along an outer circumferential surface 52 a, 54 a of the respective groove 52, 54 and inner circumferential surfaces 22g, 24g of lips 22 f, 24 f slide along an inner circumferential surface 52 b, 54 b of the respective groove 52, 54. Inner circumferential surface 52 b of annular groove 52 is defined by an annular inner circumferential lip 12 a of inlet section 12 and outer circumferential surface 52 a of annular groove 52 is defined by an annular outer circumferential lip 12 b of inlet section 12. Similarly, inner circumferential surface 54 b of annular groove 54 is defined by an annular inner circumferential lip 14 a of outlet section 14 and outer circumferential surface 54 a of annular groove 54 is defined by an annular outer circumferential lip 14 b of outlet section 14.

Inlet swash plate 22 is axially in contact with a radially extending inlet side surface 18 a of rotor 18 and an inner portion of a radially extending inlet side surface 16a of stator 16 and outlet swash plate 24 is axially in contact with a radially extending outlet side surface 18b of rotor 18 and an inner portion of a radially extending outlet side surface 16b of stator 16. Annular outer circumferential lip 12 b of inlet section 12 also contacts radially extending inlet side surface 16a of stator 16 and annular outer circumferential lip 14 b of outlet section 14 contacts radially extending outlet side surface 16b of stator 16. Inlet and outlet sections 12, 14 are provided with respective flanges 62, 64, which in this embodiment are triangular, that include through holes for receiving fasteners for clamping sections 12, 14 axially together onto stator 16. Protruding axially outward from flanges 62, 64, respectively, inlet and outlet sections 12, 14 include respective male threaded tubes 68, 70 for connecting to corresponding female threaded components.

Pump 10 also includes a controller 56 configured to control the flow of the current through electrical windings 26 to rotate the rotor. In this embodiment, controller 56 is in the form of transistors on control board for electrically commutating and controlling pump 10. Alternately, the controller can be remote and connected to windings 26 by wires.

In the embodiment shown in FIGS. 1 to 3, pump 10 is a gerotor pump; however, in other embodiments, a similar construction may be made with other pump types, including an internal gear pump or a vane pump.

In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense. 

What is claimed is:
 1. A pump comprising: a fluid inlet section; a fluid outlet section; a stator axially between the fluid inlet section and the fluid outlet section; a rotor axially between the fluid inlet section and the fluid outlet section, the rotor and the stator defining a fluid flow space radially therebetween; a movable inlet guide configured for guiding fluid flow from the fluid inlet section into the fluid flow space; and a movable outlet guide configured for guiding fluid flow from the fluid flow space into the fluid outlet section, the rotor being rotatable inside of the stator by electromagnetic forces urging the rotor towards the stator, rotation of the stator and movement of the inlet guide and the outlet guide creating a pressure in a first portion of the fluid flow space that forces fluid from the fluid flow space through the fluid outlet section and creating a vacuum in a second portion of the fluid flow space that pulls fluid from the fluid inlet section into the fluid flow space.
 2. The pump as recited in claim 1 wherein, during rotation of the stator, the movable inlet guide is configured to move to align the first portion of the fluid flow space with the fluid inlet section and the movable outlet guide is configured to move to align the second portion of the fluid flow space with the fluid outlet section.
 3. The pump as recited in claim 2 wherein the movable inlet guide is an inlet swash plate and the movable outlet guide is an outlet swash plate.
 4. The pump as recited in claim 2 wherein the rotor is eccentrically mounted within the stator for rotation.
 5. The pump as recited in claim 4 wherein the rotor is eccentrically fixed to the movable inlet guide and the movable outlet guide such that rotation of the rotor about an axis of the rotor in a first rotational direction causes the movable inlet guide and the movable outlet guide to rotate about the axis of the rotor in a second rotational direction opposite the first rotational direction.
 6. The pump as recited in claim 5 wherein the movable inlet guide and the movable outlet guide are fixed together by a pin passing axially through the rotor, the pin defining the axis of the rotor.
 7. The pump as recited in claim 6 wherein, as viewed axially, the movable inlet guide and the movable outlet guide cover different cross-sections of the fluid flow space during operation as the movable inlet guide and the movable outlet guide rotate about the pin.
 8. The pump as recited in claim 7 wherein the movable inlet guide and the movable outlet guide each including a guide portion having a semicircular cross-section when viewed axially.
 9. The pump as recited in claim 1 wherein the stator includes at least four electrical windings configured for receiving current to generate the electromagnetic forces for urging the rotor towards the stator to rotate the rotor.
 10. The pump as recited in claim 9 further comprising a controller configured to control the flow of the current through the at least four electrical windings to rotate the rotor.
 11. The pump as recited in claim 1 wherein the fluid inlet section includes an annular groove for guiding a lip of the movable inlet guide during rotation of the movable inlet guide and/or the fluid outlet section includes an annular groove for guiding a lip of the movable outlet guide during rotation of the movable outlet guide.
 12. The pump as recited in claim 1 wherein the movable inlet guide sits flush against a first radially extending axial facing surface of the stator and a first radially extending axial facing surface of the rotor and the movable outlet guide sits flush against a second radially extending axial facing surface of the stator and a second radially extending axial facing surface of the rotor.
 13. An automotive vehicle transmission comprising the pump recited in claim
 1. 14. A method of forming a comprising: providing a rotor radially inside of a stator; rotatably fixing a movable inlet guide to a first axial side of the rotor; rotatably fixing a movable outlet guide to second axial side of the rotor; providing a fluid inlet section upstream of the movable inlet guide; and providing a fluid outlet section downstream of the movable outlet guide, the rotor and the stator defining a fluid flow space radially therebetween, the movable inlet guide configured for guiding fluid flow from the fluid inlet section into the fluid flow space, the movable outlet guide configured for guiding fluid flow from the fluid flow space into the fluid outlet section, the rotor being rotatable inside of the stator by electromagnetic forces urging the rotor towards the stator, rotation of the stator and movement of the inlet guide and the outlet guide creating a pressure in a first portion of the fluid flow space that forces fluid from the fluid flow space through the fluid outlet section and creating a vacuum in a second portion of the fluid flow space that pulls fluid from the fluid inlet section into the fluid flow space.
 15. The method as recited in claim 14 wherein, during rotation of the stator, the movable inlet guide is configured to move to align the first portion of the fluid flow space with the fluid inlet section and the movable outlet guide is configured to move to align the second portion of the fluid flow space with the fluid outlet section.
 16. The method as recited in claim 15 wherein the movable inlet guide is an inlet swash plate and the movable outlet guide is an outlet swash plate.
 17. The method as recited in claim 15 wherein the rotor is eccentrically mounted within the stator for rotation.
 18. The method as recited in claim 17 wherein the rotatably fixing the movable inlet guide to the first axial side of the rotor and the rotatably fixing the movable outlet guide to the second axial side of the rotor includes eccentrically fixing the rotor to the movable inlet guide and the movable outlet guide such that rotation of the rotor about an axis of the rotor in a first rotational direction causes the movable inlet guide and the movable outlet guide to rotate about the axis of the rotor in a second rotational direction opposite the first rotational direction.
 19. The method as recited in claim 18 wherein the movable inlet guide and the movable outlet guide are fixed together by a pin passing axially through the rotor, the pin defining the axis of the rotor. 